Sixth chord

A sixth chord is a major chord or a minor chord with an added sixth interval. Typically, the added sixth is a major sixth for both the major and minor chords.

The chord C6 (or the equivalent notation CM6) is the chord composed of C, E, G, and A. The notes C, E, and G form the C major chord and the interval between C and A is a major sixth.

The chord Cm6 (or the equivalent notation Cmin/maj6) is the chord composed of C, Eb, G, and A. The notes C, Eb, and G form the C minor chord and the interval between C and A is a major sixth. Note that the sixth note on the C minor scale is Ab and not A. The sixth chord is often used on the subdominant (the fourth note) on the scale and not on the tonic (the first note). Here, a Cm6 chord can be built on the subdominant of the G minor scale, which includes the note A. The added major sixth creates a tension with the minor chord , which makes the sixth chord interesting.

Examples of scales with sixth chords

The following are examples of where the major sixth chord occurs in common heptatonic scales.

• On the first note (the tonic), fourth note (the subdominant), and fifth note (the dominant of the major scale. That is, if a major sixth chord is composed over the first, fourth, or fifth note on the major scale, then all notes in that chord will also be on the major scale.
• On the third note (the mediant), sixth (submedian), and seventh note (subtonic) of the minor scale.
• On the second note (the supertonic) of the Spanish gypsy scale.
• On the fourth note (the subdominant) of the altered scale.

The following are examples of where the minor sixth chord occurs in common heptatonic scales.

• On the first note (the tonic) of the melodic ascending minor scale and Dorian scale.
• On the third note (the mediant) of the altered scale.
• On the fourth note (the subdominant) of the minor scale.
• On the second note (the supertonic) of the major scale.

Relationships between the sixth chord and other chords

The major sixth chord on the first note of the major scale has the same notes as the minor seventh chord on the sixth note of the major scale. For example, C6 = C, E, G, A and Am7 = A, C, E, G.

The minor sixth chord Cm6 includes the notes C, Eb, G, A, which can also be the notes of F9 = F, G, A, C, Eb (with the root F omitted, which in popular music can happen often and the root can be left for another instrument to play), or the half-diminished Am7b5 = A, C, Eb, G.

A 13th chord also includes an added sixth (the thirteenth note on a heptatonic scale is the same as the sixth note). However, by convention, the 13th chord is a seventh chord with the added sixth, whereas the sixth chord does not include the seventh on the scale.

Other meanings of the term sixth chord

In the past and in classical music, the term sixth chord meant inverting a three-note chord by moving the third to the bass and the root to the top. For example, this inversion of the major C chord = C, E, G is the major C chord = E, G, C. In this form, the C is the sixth note up from the E.